The description of Google Connectivity Services

Google Connectivity Services helps Android manage Wi-Fi and other network connections. This app is only available to Project Fi and Pixel/Nexus users. Keep it updated to ensure your device has the latest Wi-Fi networking capabilities. Google Connectivity Services includes Wi-Fi assistant, which automatically connects you to high-quality public Wi-Fi, and secures those connections by transmitting your data through a secure Virtual Private Network (VPN) managed by Google.